Electronic proximity switches of the aforementioned type have been proposed which include an approximately cubic sensor housing, a rotatable angle member comprising a connecting piece with the rotatable angle member being selectively attachable in two different turning positions on a housing edge of the cubic sensor housing and a base member mounted at an installation site. The base member is generally provided with an opening for rotatably accommodating the connecting piece with the rotatable angle member, with the rotatable angle member being fixable to the base member in four rotary positions angularly spaced by 90.degree..
An advantage of an electronic proximity switch of the aforementioned type resides in the fact that it is possible to obtain a compact structure since the sensor device in the entire electronic circuit are accommodated in a relatively small essentially cubic housing; however, a disadvantage of the conventional electronic proximity switches resides in the fact that if the switch is transposed in order to change a response direction, such transposition also effects the placing of the electric connector or lead wire which then results in difficulties under cramped or tight installation conditions.
In, for example, DOS 3,515,033, a proximity switch is proposed which includes a cubic sensor housing, a rotatable angle member and a socket part, with a connector element being connected with the rotatable angle member and including an undercut annular bead at a free end face, with snap fingers joined to the socket part engaging into the undercut annular bead. A stop projection of the socket part engages into a further annular groove on an end face of the connector element extending over 270.degree. so that the rotatable angle member can be turned relative to the socket part. Locking recesses for the stop projection are provided at annular spaces of 90.degree. for enabling a fixation of the selected rotary position for the proximity switch. A base member is fashioned as a bipartite housing including a portion of the electronic circuitry and is provided with an opening for a switch connector cable.
In the last described conventional proximity switch, a change in response direction is brought about without disengagement of the mounted socket part; however, a disadvantage of the proposed construction resides in the fact that the switch is expensive to manufacture by virtue of the fact that it is constructed of a plurality of individual components and a rotational locking effect is brought about merely by locking ridges which is unsatisfactory from a safety standpoint. Moreover, in the proposed construction, the insulation of the switch connector wire which, presently is in the form of angular plugs, is extensively predetermined and adaptation in the case of cranked or tight space conditions is hardly possible.
In, for example, DOS 3,743,420, a further proximity switch is proposed wherein a rotatable angle member carrying a sensor head is provided with a square connector element adapted to be plugged into four different positions into a square receptacle opening of a socket member and fixed in position by way of a locking screw.
A disadvantage of the last mentioned proximity switch resides in the fact that in order to change response direction of the proximity switch, considerable cumbersome manipulation is necessary since the rotatable angular member can be transposed only after being pulled out from the socket member. Moreover, in each case, the socket member must be opened during the operation in order to obtain access to the locking screw.